1. Field of the Invention
This invention relates to a method for preparing lower aliphatic alcohols and to the catalyst composition used in said method. More particularly, this invention relates to the production of a mixture of lower aliphatic alcohols in the presence of a novel catalyst composition. The lower aliphatic alcohols so produced are characterized by containing a substantial proportion of alcohols having from 2 to 7 carbon atoms.
2. Description of Background Art
Lower aliphatic alcohols have been proposed as fuel extenders or as replacements for gasoline for fueling internal combustion engines. Certain mixtures of lower aliphatic alcohols have the EPA approval for use and are currently being marketed in the United States. The lower aliphatic alcohols can be produced from domestically available non-petroleum sources. Therefore, their use in fuels would serve to lessen the dependence of the nation on imported petroleum and petroleum products.
Hydrogen and carbon monoxide, or a synthesis gas mixture of hydrogen and carbon monoxide, can be reacted to form lower aliphatic alcohols or hydrocarbons. The synthesis gas feed stream can be produced from non-petroleum sources, such as coal, biomass or other hydrocarbonaceous materials. The synthesis gas mixture itself is produced, for instance, in a partial oxidation reaction of the hydrocarbonaceous material in commercially available processes, such as coal gasification.
Numerous catalysts and catalytic methods have been studied in attempts to provide a viable method for the production of aliphatic alcohols from synthesis gas or from other mixtures of hydrogen and carbon monoxide. Heretofore, the emphasis has been primarily directed to the production of methanol, in the presence of a catalyst composition which is selective for methanol production.
In contrast, the present invention is directed to a method for producing an alcohol mixture containing a substantial amount of aliphatic alcohols having from 2 to 7 carbon atoms. Under selected reaction conditions, this method, when performed in the presence of the novel catalyst composition described hereinbelow, is effective for producing a fraction of higher aliphatic alcohols, i.e., an alcohol fraction consisting of C.sub.2 to C.sub.7 alcohols, which represents the major or predominant alcohol production in this method.
U.S. Pat No. 1,201,850 discloses a method for the production of hydrocarbons and oxygenated compounds of hydrocarbons by passing an oxide of carbon and hydrogen over a heated catalytic agent under a pressure exceeding 5 atmospheres. A number of catalytic materials are disclosed as well as the fact that a basic compound, such as an alkaline metal hydroxide, can be used with the prescribed catalytic agents.
U.S. Pat. No. 1,625,929 discloses a process for producing methanol in which the catalyst contains copper, cobalt and a metallic halide.
U.S. Pat. No. 3,345,427 discloses a dehydrogenation catalyst and process in which the catalyst consists of nickel, molybdenum and alkali metal oxides on an alumina support.
U.S. Pat. No. 4,096,164 discloses a process for reacting hydrogen and carbon monoxide in the presence of a solid catalyst comprising rhodium with molybdenum or tungsten to produce two carbon atom oxygenated hydrocarbons in which ethanol is the major component.
U.S. Pat. No. 4,199,522 discloses a Fischer-Tropsch process for producing olefins and this disclosure is incorporated herein by reference.
U.S. Pat. Nos. 4,235,801 and 4,246,186 disclose the production of alcohols from a mixture of carbon monoxide and hydrogen in the presence of a rhenium catalyst.
U.S. Pat. No. 4,380,589 discloses a Fischer-Tropsch process for producing hydrocarbons with improved selectivity to C.sub.2 -C.sub.4 olefins by contacting hydrogen and carbon monoxide in the presence of a catalyst. The catalyst disclosed comprises molybdenum, a promoter comprising alkali or alkaline earth metal, and a binder comprising an iron-containing calcium aluminate cement.
U.S. Pat. No. 4,607,055 discloses a process for producing lower aliphatic alcohols from a mixture of carbon monoxide and hydrogen in the presence of a catalyst comprising molybdenum; a metal from the group consisting of cobalt, iron and nickel; and silver. The catalyst is modified by the addition of a promoter from the class consisting of potassium, cesium and rubidium. This disclosure is incorporated herein by reference.
U.S. Pat. No. 4,661,525 discloses a process for producing lower aliphatic alcohols from a mixture of carbon monoxide and hydrogen in the presence of a catalyst comprising molybdenum and a metal selected from the group consisting of cobalt, iron and nickel which has been promoted by an alkali metal selected from the group consisting of potassium, cesium and rubidium. This disclosure is incorporated herein by reference.
Co-assigned application Ser. No. 939,392 filed on Dec. 12, 1986 is directed to a process for producing lower aliphatic alcohols from a mixture of carbon monoxide and hydrogen in the presence of a catalyst comprising rhodium, molybdenum and an alkali metal. This disclosure is incorporated herein by reference.
As previously noted, prior catalytic methods have been notably effective for converting carbon monoxide and hydrogen feedstocks into hydrocarbons or methanol, but none have been particularly effective for providing high yields of a lower aliphatic alcohol mixture characterized by having a substantial amount of alcohols having from 2 to 7 carbon atoms along with the coproduced methanol and/or hydrocarbons.